That said, I'm working on a project for implementing an overlay network above bitcoin P2P for a more general purpose networking, the main challenge here is incentivizing bitcoin full nodes to participate, whether maintaining their own software repository is enough incentive or not is subject to further assessments.
That would be interesting if the full nodes (or even SPV clients) could also keep a copy of the repository and be able to share it with other clients. The repository sizes aren't that high to need a very high incentive. For example repository sizes:
bitcoin core = 218 MB
Electrum = 50 MB
Gocoin = 17 MB